Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cua triet, dua tren
duc ban » duc tan, duc van, dua ban
van cam » van nam, van lam, van cau
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cuu tre » cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thuat sach)) ky dang xa hoi. hieu van cam duc ban thanh vi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat sach)) ky dang xa hoi. hieu van cam duc ban thanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuat sach)) ky dang xa hoi. hieu van cam duc ban thanh vi ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat sach)) ky dang xa hoi. hieu van cam duc ban thanh vi ((cua tre) OR (cuu tre))*.